[Zope-DB] Taking advantage of MySQLs inbuilt chache

Charlie Clark charlie at egenix.com
Wed Mar 3 05:48:47 EST 2004

I'm returning this to the list so that everyone can benefit.

On 2004-03-03 at 11:20:25 [+0100], you wrote:
> Mainly because the memory use can build up due to my heavy use of sql. MySQL
> is fairly intelligent/efficient in expiring caches and on our Debian Linux
> box these Zope SQL caches do not appear to have their memory reclaimed when
> they expire - (though I can't definitively say that is where my leak is)
> meaning I have to restart Zope every week.

This is interesting and sounds like a bug. Which version of Zope are you 
running? Doesn't clearing the general Zope cache make a difference?
> It shouldn't need anything other than the standard SQL to take advantage of
> the cache as all it needs is a 2nd SELECT query that has exact same binary
> size of the 1st but for some reason the direct MySQL drivers don't seem to
> 'hit' the cache suggesting that even though the plain text SQL is the same
> the processed query is somehow a different binary size to MYSQL each time.

Interesting. I wonder if this is a standard mechanism for query optimisers.
> Maybe if I try the mxODBC drivers they might work :)

yeah, give them a try and let us know!
Charlie Clark

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